A lighting fixture (illumination device) described in JP 2014-86166 A (hereinafter referred to as “Document 1”) is illustrated as a conventional example. The lighting fixture of the conventional example is a line type lighting fixture that is provided in an embedded state on a ceiling, and includes an elongated main body, a light source, and a lighting apparatus (power supply device).
The light source is constituted by a plurality of light-emitting diodes (LEDs) being mounted on a mounting substrate. The lighting apparatus includes a power supply unit, an individual control unit, a signal terminal board, and a power supply terminal board. Note that the lighting apparatus is configured such that the configuration thereof can be selected from a configuration in which the individual control unit is included and a configuration in which the individual control unit is not included.
The power supply unit includes a case shaped like a rectangular parallelepiped, and a signal input terminal and a power input terminal are arranged side by side in a short direction of the case in one end portion in a longitudinal direction of the case. An external power supply (such as an AC power supply having an effective value of 100 V or 200 V) is electrically connected to the power input terminal. Also, the signal input terminal is electrically connected to the signal terminal board directly or via the individual control unit. Furthermore, an output terminal is provided in the other end portion in the longitudinal direction of the case. The light source is electrically connected to the output terminal. The power supply unit is configured to convert an AC voltage (AC current) that is received from the power input terminal to a DC voltage (DC current), and output the DC voltage (DC current) from the output terminal.
Control signals for controlling lighting of the light source directly or via the individual control unit are inputted to the signal terminal board from the outside of the lighting fixture. The external control signals include a signal from a human sensor that monitors the presence or absence of a person inside a detection area, a signal from a brightness sensor that monitors the brightness in the detection area, a signal from a wall switch on which manual operations such as turning on or off and selecting a scene are performed.
The individual control unit receives an external control signal via the signal terminal board, and acquires address data and control command data that are included in the external control signal. The individual control unit then outputs, when the acquired address data matches its own address data, a light modulation signal (such as a PWM light modulation signal) based on the acquired control command data to the signal input terminal of the power supply unit.
The power supply unit controls the magnitude of the output electric power and power supply time (lighting time) based on the PWM light modulation signal that is inputted to the signal input terminal, and controls the lighting state of the light source.
In the conventional example described in Document 1, the operations of the power supply unit with respect to the external control signal can be changed according to the presence or absence of the individual control unit, as described above.
Incidentally, in the power supply unit of the above conventional example, the signal input terminal to which the individual control unit is electrically connected is arranged adjacent to the power input terminal. Therefore, it has been difficult to miniaturize the power supply unit, if a spatial distance regulated by law (Electrical Appliances and Materials Safety Act, in Japan) between the signal input terminal and the power input terminal is to be secured.